1. Field of the Invention
The present invention relates to a radar reflector apparatus that is mounted in a lifeboat or a small rescue boat or in a floating buoy used for salvage or search practice, or is used by itself independently, to serve as a radar wave reflector of a search radar. In particular, the invention relates to a radar reflector apparatus with a simple structure, that is folded when not in use, and when used, is unfolded automatically when dropped by a marine vessel or aircraft or the like.
2. Description of the Related Art
One conventional radar reflector apparatus of this type is known as a folding reflector. In this folding reflector apparatus, there are prepared three rectangular plates each of which is formed with a slit running up to the center along a diagonal line from one corner portion of a rectangular plate towards the opposite comer portion, and the three rectangular plates are assembled by fitting the slits together so that the three rectangular plates intersect each other at right angles at comer portions, thereby forming a comer section that reflects radar waves.
Another type of radar reflector apparatus is an automatically unfolding type that employs gas. In this unfolding type radar reflector apparatus, reflective plates with flexibility substantially the same as the plates of the above folding reflector apparatus are placed inside a vinyl ball shaped like a beach ball. When not in use, the internal gas is released and the vinyl ball is folded. When used, a carbon dioxide gas cartridge, for example, installed inside the vinyl ball is operated so as to fill the interior of the vinyl ball with carbon dioxide gas. The vinyl ball is thus inflated and the reflective plates inside the vinyl ball are unfolded.
However, in the above conventional folding reflector apparatus, at the time of use, it is necessary for a user on-site to assemble the three rectangular plates by fitting together the slits. This operation may be troublesome, and there have been cases where the apparatus has not been able to be employed rapidly. Moreover, in the automatic unfolding type radar reflector apparatus that employs a vinyl ball, the above problem does not occur because the reflective plates are unfolded automatically at the time of use. However, it is necessary for the flexible reflective plates to be placed inside the vinyl ball and for a carbon dioxide gas cartridge to be installed inside the vinyl ball. As a result, the structure becomes complex and the manufacturing cost of this apparatus becomes high.
In order to solve the above problems, it is an object of the present invention to provide a radar reflector apparatus with a simple structure, that is folded when not in use, and when used, is unfolded automatically when dropped by, for example, a marine vessel or aircraft or the like.
In order to achieve the above object, the radar reflector apparatus according to the present invention comprises: a support pillar standing vertically upright; a plurality of arms joined to a lower end portion of the support pillar, that are unfolded from a folded state in which they are substantially parallel to the support pillar to a state in which they are substantially perpendicular to the support pillar so as to be positioned in radial; elastic members provided between the support pillar and each arm, that unfolds the arms from the folded state in which they are substantially parallel to the support pillar to the state in which they are substantially perpendicular to the support pillar; and flexible reflective membranes provided under tension between the support pillar and the respective arms and between adjacent arms, that are capable of being folded and unfolded.
According to the above construction, it is possible to unfold the plurality of arms joined to the lower end portion of the support pillar standing vertically upright from the folded state in which the arms are substantially parallel to the support pillar to the state in which they are substantially perpendicular to the support pillar, using the elastic members provided between the support pillar and the respective arms, and also to unfold the flexible reflective membranes provided under tension between the support pillar and the respective the arms and between adjacent arms. Accordingly, it is possible to provide a radar reflector apparatus with a simple structure, that is folded when not in use, and when used, is unfolded automatically when dropped by, for example, the marine vessel or aircraft or the like. In addition, since the structure is simple, it is possible to achieve a reduction in cost.